package training;

import java.util.Scanner;
// https://www.nowcoder.com/questionTerminal/3549ff22ae2c4da4890e9ad0ccb6150d
// 注意类名必须为 test.Main, 不要有任何 package xxx 信息
public class Day33_02 {
    private static long[] arr = new long[81];
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        cal();
//        for (int i = 0; i < arr.length; i++) {
//            System.out.println(arr[i]);
//        }
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int a = in.nextInt();
            int b = in.nextInt();
            int sum = 0;
            for(int i = a-1; i < b; i++){
                sum += arr[i];
            }
            System.out.println(sum);
        }
    }
    public static void cal(){
        arr[0] = 1;
        arr[1] = 1;
        long tmp1 = arr[0];
        long tmp2 = arr[1];
        for(int i = 2; i < arr.length; i++){
            arr[i] = tmp1 + tmp2;
            tmp1 = tmp2;
            tmp2 = arr[i];
            // arr[i] = arr[i-1] + arr[i-2];
        }
    }
}
